did they tell you when they were going to make their decision?
If yes: then wait until After their decision date. If you don't hear from them you can always just call and say you were following up on a resume you turned in etc etc etc.
If no: you can call them and tell them you forgot to ask at the time you submitted your resume when they were planning on making their decision. You might also ask them if they will call you and let you know once the decision has been made even if they hired someone else.
and always thank them for their time! I know that sounds very formal but sometimes its the little things like that that make a big impression.
Life should NOT be a journey to the grave with the intention of arriving safely in an attractive and well preserved body, but rather to skid in sideways, champagne in one hand, strawberries in the other, body thoroughly used up, totally worn out and screaming: "Yeah Baby! What a Ride!"